The present invention refers to a method and apparatus for curtain coating a moving support with a liquid coating material. Especially in wide machines and at high speeds, curtain coating involves a great number of problems with respect to the stabilization of the liquid curtain and an even application thereof to the support. One of these problems is the fact that the freely falling liquid film is forwardly deformed, i.e. in the direction of the moving support. This divergence from the perpendicular falling direction is caused by the boundary layer of air which is carried along by the support.
Different methods and apparatus for the stabilization of the liquid curtain in this respect are known. Thus, amongst others, a coating installation is known from EP-A-0 489 978 which comprises an air shield which, seen in the direction of the moving support, is disposed in front of the liquid film and is provided with an opening from which the air stemmed in said shield is evacuated. Due to the use of a shield, the distance between the point where the air is evacuated and the curtain is quite large, whereby the efficiency of the device is reduced. Furthermore, a method and device for curtain coating is known from EP-A-0,551,237, wherein a stabilization of the air in front of the curtain is attempted by measuring the air pressure in the space in front of the pouring curtain in order to supply or remove air on the basis of a reference value. However, a precise control requires a complicated apparatus in order to maintain a uniform air pressure across the entire width of the machine.